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1.
巴天酸模中的蒽醌类化合物 总被引:2,自引:0,他引:2
从巴天酸模 (PolygonumRumexPatientiaL .)的全草中分离得到 6个蒽醌类化合物 ,由光谱数据鉴定了其结构 .分别是大黄素 (emodin ,Ⅰ ) ,大黄酚 (chrysophanol,Ⅱ ) ,大黄素甲醚 (physcion ,Ⅲ ) ,大黄素 1,6 二甲醚 (emodin dimethylether,Ⅳ ) ,大黄素 8 O β D 葡萄糖甙 (emodin 8 O β D glucoside ,Ⅴ )和xanthorin 5 methylether(Ⅵ ) .其中 ,化合物Ⅴ和Ⅵ系首次从该植物中分得 相似文献
2.
石香薷中的黄酮体化合物 总被引:3,自引:0,他引:3
从石香薷中分出四个黄酮类化合物 ,通过光谱分析及结合标样对照 ,确定其结构分别为 5 ,7 二甲氧基 4’ 羟基黄酮 (1) ,芹菜素 7 O а L鼠李糖 (1→ 4 ) 6” O 乙酰基 β D 葡萄糖甙 (2 ) ,5、7 二甲氧基 4’ O α L 鼠李糖 (1→ 2 ) β D 葡萄糖甙 (3)及金合欢素 7 O 芸香甙 (4) . 相似文献
3.
八月扎化学成分的研究 总被引:6,自引:0,他引:6
从八月扎(FructusAkebiae)中分离出13个化合物,并进行了分离纯化和结构鉴定,分别为1 monostearin(1),2 monoolein(2),1 monoolein(3),棕榈酸(4),1 acetyl 3 olein(5),1 acetyl 3 linoleoyin(6),β 谷甾醇(7),β 胡萝卜甙(8),常春藤皂甙元 3 O β 葡萄吡喃糖甙(9),常春藤皂甙元 28 β D 葡萄吡喃糖甙(10),常春藤皂甙元 3 O β D吡喃木糖基(1→2) α L 阿拉伯吡喃糖(11),常春藤皂甙元 3 O α L 吡喃鼠李糖基(1→2) α L 阿拉伯吡喃糖甙(12),常春藤皂甙元 3 O β D 葡萄糖吡喃基(1→2) α L 吡喃鼠李糖基(1→3) α L 吡喃木糖基甙(13).其中化合物1~6,9,10,12,13为首次从该植物中分离得到. 相似文献
4.
对裂叶荆芥芥穗化学成分进行了研究。从70%乙醇提取物中首次分得4个黄酮和2个单萜类化合物单体,经化学和光谱学分析,它们分别为:5,7-二羟基-4,6-二甲氧基黄酮、木犀草素-7-氧-葡萄糖甙、3′-羟基-4′,6,8-三甲氧基二氢黄酮-7-氧-芸香糖甙、5-甲基-3′-羟基-4′,6-二甲氧基二氢黄酮-7-氧-芸香糖甙、脱氢枞油烯和荆芥内酯。所有化合物均为首次从该科植物中获得。 相似文献
5.
蝎子七化学成分的研究 总被引:4,自引:0,他引:4
从甘肃天祝县的蝎子七全草中分离鉴定出了15个化合物,其中2个为新化合物,报道9个已知化合物:阿魏酸、4-豆甾烯-3-酮、紫丁香甙、5,8,2′-三羟基-5′—甲氧基双氢黄酮、异鼠李素、槲皮素-3-O-鼠李素、山奈素-3-O-β-D-葡萄糖甙、洋芥素-7-O-β-D-葡萄糖甙、5-羟基-4-甲氧基黄酮-7-O-β-芸香甙。上述成分均首次从该植物中分离。 相似文献
6.
从野紫苏中分得6个黄酮类化合物,经理化性质和波谱数据分析,确定为5,7-二羟基-4’-甲氧基黄酮1;5-羟基-7,4’-二甲氧基双氢黄酮醇2;山奈酚-3-O-β-D-葡萄糖甙3;檞皮素-3-O-β-D-葡萄糖甙4;5-羟基-3’-甲氧基双氢黄酮-7-O-芸香糖甙5;5-羟基-4’-甲氧基黄酮-7-O-芸香糖甙6。除化合物1和2外,其余4个黄酮类化合物为首次从该属植物中得到。 相似文献
7.
从团花树皮中分离得到6个环烯醚萜类化合物.根据光谱数据和理化性质鉴定它们的结构分别为马钱素甙元(Ⅰ),马钱素(Ⅱ),马钱酸(Ⅲ), 8-表金吉甙(Ⅳ),当药甙(Ⅴ),3′-O-咖啡酰当药甙(Ⅵ).其中Ⅰ~Ⅴ均为首次从该植物中分离得到,Ⅵ为新化合物. 相似文献
8.
《西北师范大学学报(自然科学版)》2016,(1)
从豆科植物九龙藤(Bauhinia championii Benth)的乙醇提取物中分离出7个已知黄酮类化合物,经过核磁共振谱(NMR)和质谱(MS)分析及标准品对照,鉴定了它们的结构,分别为:5,6,7,5′-四甲氧基-3′,4′-亚甲二氧基黄酮(1),5,6,7,3′,4′,5′-六甲氧基黄酮(2),5,7,3′,4′,5′-五甲氧基黄酮(3),5,6,7,3′,4′-五甲氧基黄酮(甜橙素)(4),5,7,4′-三甲氧基黄酮(5),5,7,3′,4′-四甲氧基黄酮(6),(-)-表阿夫儿茶素(7).其中化合物5,7为首次从该植物中分离得到. 相似文献
9.
2-芳基-5-(2′,3′,4′,6′-四-O-乙酰基-β-D-吡喃葡萄糖基)亚胺基1,3,4-噻二唑化合物的合成及其生物活性 总被引:1,自引:0,他引:1
将 2 ,3,4 ,6 四 O 乙酰基 β D 吡喃葡萄糖基异硫氰酸酯分别与水合肼和芳醛发生反应 ,得到了希夫碱 芳香醛缩N 氨基 N′ ( 2 ,3,4 ,6 四 O 乙酰基 β D 吡喃葡萄糖基 )硫脲 ,在K3 [Fe(CN) 6]和NaOH存在下于醇液中环化制得 2 芳基 5 ( 2′ ,3′,4′,6′ 四 O 乙酰基 β D 吡喃葡萄糖基 )亚胺基 1,3,4 噻二唑化合物。利用红外光谱、核磁共振氢谱对目标化合物进行了结构表征。生物活性初步测试结果表明 ,目标化合物对黄瓜赤霉、棉花立枯、玉米大斑、苹果黑斑、花生褐斑和小麦赤霉菌 6种植树原菌的繁殖均有不同程度的抑制作用 相似文献
10.
应用一条新的合成路线合成了尚未见文献报导的黄酮 4′ O 糖苷8:先由庚二酰氯1与对甲氧基苯乙酮的烯胺2反应生成4′ 甲氧基四氢黄酮3,再经脱氢、脱甲基得到4′ 羟基黄酮5,最后与1 溴 2,3,4,6 O 四乙酰基 α D 吡喃葡萄糖进行缩合生成了黄酮 4′ O 糖苷8. 相似文献
11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
12.
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
13.
QING Hai-ruo 《成都理工大学学报(自然科学版)》2004,31(6)
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction. 相似文献
14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
16.
YUJia-shun HEZhen-hua 《成都理工大学学报(自然科学版)》2004,31(6):694-698
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod… 相似文献
17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying. 相似文献
18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time. 相似文献
19.
Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
20.
Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献